Rape and sexual assault are highly prevalent, and sexual aggression potentially places men and their unwilling female partners at risk for HIV and other sexually transmitted infections (STIs). Yet, the factors that contribute to young men's sexually aggressive behavior are poorly understood, and the association between sexual aggression and HIV/STI risk has been virtually unexamined in past research. This project attempts to address these gaps by investigating how men's sex role identity may function independently and in combination with negative affect and emotional dysregulation to predict men's sexual aggression and other forms of sexual risk-taking (i.e., behaviors that place men and their partners at risk for HIV and STIs). For this project, we will recruit a sample of men at high risk for HIV and other STIs from two urban areas. The proposed project will employ questionnaire, interview, and laboratory methods to (1) assess the relationship between sexual aggression and other sexual risk-taking and (2) to test and refine an intervention-oriented model that predicts young men's sexual aggression and HIV risk behavior. Specifically, in Study 1, 400 young men will complete questionnaires that assess their hypermasculinity, their proneness to negative emotions, their emotional dysregulation, and their history of sexual aggression and other sexual risk-taking. These data will be used to evaluate a hypothesized model of sexual aggression and sexual risk-taking. In Study 2, approximately 50 men with and without a history of high risk sexual behavior will be invited to participate in focus groups and individual interviews. Information from these interviews will be used to refine the proposed model of sexual aggression and HIV risk. Finally, in Study 3, 40 high HIV risk and 40 low HIV risk men will be brought into the laboratory to experimentally assess the role of negative affect and emotional dysregulation in men's sexual aggression and HIV/STI risk. The long-term goals of this project are to better understand the risk factors that are common to sexual aggression and other sexual risk-taking and to identify strategies that can be applied to rape and HIV prevention programs aimed at young, heterosexual men. Based on research using nationally representative samples, sexual aggression, perpetrated by men against women, is highly prevalent, with about 18% of women reporting an experience with rape (Tjaden &Thoennes, 2000), 22% reporting a sexual assault (Laumann, Gagnon, Michael, &Michaels, 1994), and 34% reporting sexual coercion (Basile, 2002). Sexual aggression can result in many negative physical and psychological consequences for female victims, and when men perpetrate sexual aggression, they potentially place themselves and their victims at risk for HIV and other STIs. By better understanding the relationship between sexual aggression and other sexual risk-taking and by identifying the common risk factors for these behaviors, researchers could develop effective strategies to reduce sexual aggression and HIV risk among heterosexual men and their partners.